This invention relates to a connector alignment tool. More particularly, it relates to a tool that aligns and constrains the leads of a connector while the leads are inserted in the holes of the electronic package to which the connector is to be attached.
Electronic products usually consist of several levels of packages. The first level package is the semiconductor or integrated circuit (IC) package. These packages are affixed in some manner, usually by soldering, to the second level package.
The second level package, usually a printed circuit board, mechanically supports the first level packages and electrically interconnects them by means of the printed traces of the board. The second level package has some form of connector attached to it which is plugged into a mating connector on the third level of packaging.
The third level of packaging, typically called a backplane, generally consists of a printed circuit board with a number of connectors attached thereto. The printed traces of the printed circuit board interconnect the second level packages when they are plugged into the connectors of the third level package. The third level of packaging may also include mechanical elements to provide mechanical support for the second level packages. Depending upon the size and complexity of the electronic product, additional levels of packaging may be used.
As integrated circuit (IC) technology has advanced to what is now called large scale integration (LSI) and very large scale integration (VLSI), the number of electronic functions that can be performed by a first level package has increased dramatically. This has required that the number of input/output (I/O) pins, or leads, on the first level package be increased in order to utilize the increased capability. Further, when LSI or VLSI IC's are used, the number of I/O connections required on the second level package increases. For example, second level packages with more than a thousand I/O connections are now being used.
In the electronics industry, it is advantageous to keep the size of each level of packaging as small as practical. Thus, as the need for more I/O pins on the second level package has increased, smaller and more dense connectors have been developed. (In this discussion, the term "pin" is used for either of the two mating parts of a connection, e.g., for both a pin and a socket.) It is known in the art to use connectors with 400 pins arranged in four rows of 100 each, with 0.050 inch spacing between rows, and between pins in the rows.
Such multi-pin connectors utilize pins that are typically formed from a copper alloy and then plated with a thin layer of gold approximately 30 micro-inches thick. The copper gives good electrical conductivity, the alloying metal adds some strength, and the gold plating prevents oxidation which would increase contact resistance. The pins are inserted in the holes of a molded connector body which is made of plastic or of some other suitable material. The pin is formed such that when inserted in the connector body, it cannot be removed without the use of a special tool. A portion of the pin, called the lead, protrudes from the connector body. The protruding leads of all the pins are inserted into plated through holes of the printed circuit board of the second level package (or an equivalent connector of any level of packaging) and soldered or otherwise bonded or secured in their inserted position.
Disadvantageously, the pins are not rigidly held within the connector body. By design, at least the detached end of the leads, and often the socket too, must be free to move slightly so that when two connectors are engaged, the pins of the two connectors can move as they mate together. Without this ability to move slightly, one or both of the pins may be damaged due to a slight misalignment between them. Unfortunately, this means that even though the holes of the connector body and the holes of the printed circuit board are formed in the same pattern, the ends of the leads which must be inserted into the holes of the printed circuit board or other mating connector are not necessarily in the same pattern.
In the prior art, this misalignment between the ends of the leads and the holes of the printed circuit board or other connector adds considerably to the assembly cost of the package. During assembly, extreme care must be taken to ensure that all the leads are in line with the appropriate hole before applying force to insert the leads. In the past, this has been done by placing the leads over the holes and jiggling the connector while adjusting the position of the ends of the leads. The process is very time consuming because of the number of leads involved and their close spacing. In the case of the 400 pin connector described above, the process of aligning all the leads before inserting them into the holes of a printed circuit board has taken as long as three hours.
Adversely, the leads, being made of a copper alloy, are relatively easy to bend. If force is applied to the connector to insert the leads into the holes while some of the leads are still misaligned, those leads will be bent. This means that the connector must be removed, the bent leads straightened, and the process started over. Also, the forces exerted on the leads as they bend may push the pin against the connector body and damage the pin within the connector body. This may require that the expensive connector be discarded. Even worse, the damaged pin may not be noticed. In that case, the connector would be soldered to the printed circuit board and may damage its mating pin when the connector is engaged with another connector. If this happens, then two connectors must be removed and repaired, or replaced.
It is evident therefore that a need exists in the art for a tool that aligns the leads of a connector while they are inserted into the holes of the package to which the connector is to be attached. Such a tool is needed to lower the assembly cost. The assembly cost may be lowered by reducing the assembly time, and by reducing the damage caused to the connectors during the assembly process.